Beyond the Modification Degree: Impact of Raw Material on Physicochemical Properties of Gelatin Type A and Type B Methacryloyls

Abstract

Gelatin methacryloyl (acetyl) (GM(A)) is increasingly investigated for various applications in life sciences and medicine, for example, drug release or tissue engineering. Gelatin type A and type B are utilized for GAM(A) and GBM(A) preparation, but the impact of gelatin raw material on modification reaction and resulting polymer properties is rather unknown so far. Therefore, the degrees of modification (DMA) and physicochemical properties of five GAM(A) and GBM(A) derivatives are compared: The degrees of methacryloylation (0.32–0.98 mmol g−1) are indistinguishable for GAM(A) and GBM(A) as are the sol‐gel temperatures. Isoelectric points, solution viscosities, and hydrodynamic radii which are distinct for GA and GB, converge with increasing DMA. Interestingly, differences are measured for the storage moduli and equilibrium degrees of swelling of respective GA and GB derivative‐based hydrogels, in spite of their comparable DMA. This underlines the importance of GM(A) characterization beyond the modification degree.

Advanced gelatin-based vascularization bioinks for extrusion-based bioprinting of vascularized bone equivalents

“…We changed the formulation by supplementing 1.5-3 wt% unmodified gelatin (GM + G) and by additional replacement of 1.25 wt% GM by 1.25 wt% GMA (GM + G + GMA). We applied a sophisticated trial-and error-approach, which was based on our own knowledge on the gelatin-based materials and on that of others 22,28,45,46 . The viscosity and thermal gelation of the initial formulation of the vascularization ink containing 5.75% (w/w) GM was too low to achieve stable hydrogel structures after extrusion at 20-22 °C.…”

“…In contrast, GMA has relatively lower viscosities than GM, lower thermal gelation temperatures, and a lower capacity of chemical crosslinking. Such characteristics are assigned to steric effects of the additionally inserted, non-reactive acetyl-functions at constant amounts of crosslinkable methacryl-functions 45,46 . Consequently, our hypothesis was that partly exchange of GM with GMA could counteract to a potential increase of viscosity during the actual extrusion process without changing the final biopolymer concentration of the hydrogel.…”

Azido‐functionalized gelatin via direct conversion of lysine amino groups by diazo transfer as a building block for biofunctional hydrogels

“…Confocal laser scanning microscopy (LSM) was carried out using the device LSM 710 from Carl Zeiss AG (Oberkochen, Germany (Sewald et al, 2018) being based on the deionization method of Janus, Kenchington, and Ward (1951). In short, gelatin and its derivatives were dissolved in ultrapure water (5% wt/vol) at 60 C (unmodified gelatin) or 40 C (azido-modified gelatin, AzGel) and shaking.…”

Impact of endotoxins in gelatine hydrogels on chondrogenic differentiation and inflammatory cytokine secretionin vitro

“…GelMAs in the production of collagen type I. Gelatine types A and B are produced in different ways 59 , which results in different isoelectric points 60 and can influence degree of methacrylation and molecular weight 59 . Furthermore, the species and tissue type from which the gelatine is extracted could influence cell response 52,53 .…”